Treating cotton fibers to produce woollike effects



Patented June 11, 1929. I

' UNITED STATES ALBERT BODMER, F WATTWIL, SWITZERLAND, ASSIGNOR TOHEBERLEIN & CO. A.

OF WATTWIL, SWITZERLAND, A CORPORATION OF SWITZERLAND.

PATENT OFFICE.

TREATING COTTON FIBERS TO nonucn WOOLLIKE EFF'EcTs.

No Drawing. Application filed September 8, 1926, Serial N'o..134,332,'and in Germany September 16, 1925.

My invention relates to process of treating cotton goods, and moreparticularly the 1nvention relates to a process of producing cottongoods with a wool-like finish.

5 It is well known that cotton may be treated with (concentrated) nitricacid to thereby produce a good permanent finish Wool-like effectresembling wool in looks, feel and in caloric quality. This treatment asis now well known in the art, may be produced with or without apreliminary mercerization treatment. As an example of a treatment ofcotton goods by nitric acid to produce a woollike effect, reference ismade to United States Letters Patent, No. 1,439,515, to GeorgesHeberlein, patented. December 19, 1922, wherein such a process isdescribed and claimed.

However, when cotton is processed with nitric acid to producesaid-permanent finish wool effect, certain properties are attendant inthe resultant product which are highly undesirable in textile materials.For example, vegetable fibrous material, such as cotton,

2 which has been modified in this manner, possesses a yellowish color,and it also has a very great aflinity for dyes. and consequently theuniform coloring of such a product isextremely difficult. In addition,these products are very sentive to alkali, so much so that even awashing with soda is attended with injury to the fibers, so that whenone cannot bleach the goods to remove the yellow color without damage tothe goods. Dyeing with vat dyes in an alkali bath likewise brings abouta weakening of .the material.

The object of this invention is to improve such nitrated permanentfinish textile ma-. terial's, by overcoming these objectionable 40characteristics.

The invention comprises the improved product and also the process ofproducing same. The-invention will be more readily understood from thefollowing description; including one or more examples of how the productmay be produced; and the invention will be more fully set forth in theappended claims. I 1

Upon making. investigations, I have observed that small quantities ofnitrogen are always absorbed and retained by the fibers in the treatmentof the cotton with nitric acid. And I have discovered that if the fibersthat have been thus treated are denitrated, the surprising fact becomesmanifest, that the afiinity for dyes has reverted to a normal amount andthat at the same time the sensitiveness to alkali has disappeared.Besides this, a more extensive modification in the structure of thefiber has taken place whichmanifests itself in a considerableheightening of the fiber. The resistance to alkali that is attained alsoresults in greatly increasing the fastness as to color; and thepermanence of textiles thathave been improved in this manner.

While nitrated cotton wool eflects, i. e., those produced by treatmentwith nitric acid, have been very excellent as to their wool qualities,yet the above-mentioned detrimental characteristics have been such as togreatly curb an extensive commercial use of the same; but by the simpletreatment according to this invention, .not only have all of theseobjections been overcome, but the wool effect itself is actuallyimproved.

. This denitration may be carried out in any suitable manner. Forexample, I have'found it to be satisfactory to denitrate in a mannersimilar to the method used in the production of artificial silk fromcellulose nitrate; and furthermore, the denitrating agents that are inuse or are suitable for use in the production of artificial silkfrom-cellulose nitrate.

are likewise satisfactory in connection with my invention. Thus by wayof example, there are found to he satisfacto especially the sulfides andsulfohydrates 0 the alkalis, alkaline earths and ammonium, in whichconnection these agents may be used singly.

Also the salts of the low stages of oxidation of multivalent While anysuitable denitrating treatment andwashing,

may be used, I give by way of example only, the following treatmentsthat have been found to give satisfactory results:

Example No; 1.

and are washed out, soured, washed and dried. Goods thus pretreated areex osedfi to the action of nitric acid with an aci content of about 72%for about 8 minutes, and are washed out in denitrating bath tion of NaSHand goods may remain in the bath at room temperature for instance for i30 to 60 minutes, then bleached and dyedof cotton fabrics, for theinvention is also Example 2.

a denitrating bath This may consist of a% solu-' applicable to thetreatment of yarns and threads made of cotton fiber, and by the termgoods I wish to be understood as including cotton fabrics and yarns norto any particular denitrating treatment; and while the dewith nitratedwool efl'ects on cotton fibers, it may also be useful in connection withother uitrated effects on cotton goods having some of the foregoingobjections.

Having thus described myinvention, what i I claim as new anddesire tosecure by Letters Patent, is:

nitration is especially useful in connection 1. Method of treatin cottongoods which comprises producing t ereon a permanent finish wool-likeeffect by treating the goods with nitric acid, denitrating the goods torender them less sensitive to alkali prior to any finishingtreatmentinvolvin alkali, and subsequently treating the goods with an alkalisubstance to further finish the same.

2. Method of treating cotton goods which comprises producing thereon apermanent finish wool-like effect by treatin the goods with nitric acid,reducing the afl iity of the goods for dyes and increasing the fastnes'sof the color by denitrating the goods, prior to any dyeing or othertreatment involving an alkali, and subsequently dyeing the goods with adye containing alkali.

In testimony whereof I name to this specification,

ALBERT BODMER.

have signed I

